Fluorinated acrylamide silane monomers and polymers

ABSTRACT

The present invention provides novel fluorinated acrylamide silane monomers which are useful as adhesion promoting agents in optical fiber cladding compositions. Polymerization of the novel monomers, optionally in the presence compatible ethylenically-unsaturated monomers, provides homopolymers and copolymers which are useful as non-wetting agents.

This is a division of application Ser. No. 07/749,926 filed Aug. 26,1991 now U.S. Pat. No. 5,210,248.

FIELD OF THE INVENTION

This invention relates to novel fluorinated, acrylamide silane monomers,homopolymers and copolymers thereof, and a process therefor. Themonomers are useful adhesion-promoting components in claddingcompositions that are curable by actinic radiation and can be used tosurround or cover a siliceous or polymeric core to provide an opticalfiber or waveguide. The homopolymers and copolymers are useful asnon-wetting agents.

BACKGROUND OF THE INVENTION

Silane coupling agents having ambifunctionality are known in the art toprovide a stable bond between two dissimilar substrates, usually organicto inorganic, such as organic polymers to inorganic substrates, e.g.,glass, mineral fillers, metals, and metallic oxides. The bond betweenthe inorganic and organic components generally results in greaterstrength and service life to the polymer.

Polymerizable silane coupling agents are commercially available fromnumerous sources. Despite their general availability, however, onlynonfluorinated hydrocarbon materials are known. The polymerizable groupcontains either (meth)acrylate, allyl, styryl, amino, or epoxyfunctionalities, while the silane group is usually an alkoxy silylmoiety (generally methoxy or ethoxy) which serves as a binding site tohydroxy-functional inorganic substrates via displacement of the alkoxygroups. Additional information concerning silane coupling agents may befound in the book by E. P. Pleuddeman ("Silane Coupling Agents", PlenumPress: New York, 1982, p 20-23 and 97), as well as in technical reportsby S. Sterman and J. G. Marsden entitled "Theory of Mechanisms of SilaneCoupling Agents in Glass Reinforced and Filled Thermoplastic andThermosetting Resin Systems", Union Carbide Corporation, New York, and"A Guide to Dow Corning Silane Coupling Agents", Dow CorningCorporation, 1985, pp 2-13.

Substitution of fluorine for hydrogen in polymers and coatings is oftendesirable to impart useful properties such as lower surface energy.Typically, incorporation of fluorine into polymers and coatings has beenmade by copolymerizing (meth)acrylate monomers derived from(meth)acrylic acid and highly fluorinated alcohols. However,(meth)acrylates often polymerize at slow rates and provide polymerswhich possess inadequate thermal and hydrolytic stabilities.

Fluorinated (meth)acrylamide monomers have been described in severalpatents. U.S. Pat. Nos. 2,743,297 and 3,997,604 disclose fluorinated(meth)acrylamide monomers prepared by the reaction of fluorinatedsecondary or primary amines and (meth)acryloyl chloride. A complicationin the synthesis is the removal of by-product hydrogen chloride.

2-Alkenyl azlactones are known to react with certain nucleophiles suchas primary amines and alcohols to afford (meth)acrylamide-functionalproducts. It has been disclosed in U.S. Pat. No. 4,931,582 that linearfluorinated-alcohols and -diols when reacted with 2-alkenyl azlactonesyield desirable fluorinated acrylamide monomers.

It is believed that the reaction of a hydroxy-functional fluorinatedacrylamide and an isocyanatoalkylsilane to afford fluorinated acrylamidesilane monomers of the invention has not been previously reported.

SUMMARY OF THE INVENTION

Briefly, the present invention provides novel fluorinated acrylamidesilane monomers and homo- and copolymers prepared therefrom.

The fluorinated acrylamide silane monomers are prepared by a two-stepprocess. The initial reaction involves 2-alkenyl azlactones reactingwith fluorinated diols to afford a hydroxy-functional fluorinatedacrylamide. The second step involves the reaction of the aforementionedhydroxy-functional compound with an isocyanatoalkylsilane to yieldfluorinated acrylamide silane monomers of the invention. The reactionsare efficient and lack formation of side-products. The reaction productsprovide for high adhesion between a siliceous surface, i.e., a siliconbased glass, and an organic polymer coating containing the polymerizedfluorinated acrylamide silane of the invention, as would be useful, forexample, to secure a cladding material to a siliceous core in a fiberoptics construction.

Novel polymeric compositions that are useful as claddings for opticalfibers are the free radical polymerization products of coatingcompositions which are disclosed in assignee's copending patentapplication U.S. Ser. No. 07/750,092 now U.S. Pat. No. 5,239,026. filedthe same date as this application, which is incorporated herein byreference.

In this application:

"acrylamide" and "acrylate" are used in a generic sense and mean notonly derivatives of acrylic acid, but also methacrylic and othermodified acrylic acids including both so-called acryloyl, i.e.,2-propenoyl, and methacryloyl, i.e., 2-methyl-2-propenoyl, amine andalcohol derivatives, respectively;

"alkyl" and "alkylene" mean the monovalent and divalent residuesremaining after removal of one and two hydrogen atoms, respectively,from a linear or branched chain hydrocarbon having 1 to 20 carbon atoms;

"lower alkyl" means C₁ to C₄ alkyl;

"aryl" and "arylene" mean the monovalent and divalent residues remainingafter removal of one and two hydrogen atoms, respectively, from anaromatic compound (single ring and multi- and fused-rings) having 5 to12 ring atoms and includes substituted aromatics such as lower alkaryland aralkyl, lower alkoxy, N,N-di(lower alkyl)amino, nitro, cyano, halo,and lower alkyl carboxylic ester, wherein "lower" means C₁ to C₄ ;

"azlactone" means 2-oxazolin-5-ones of Formula I and 2-oxazin-6-ones ofFormula II: ##STR1##

"cycloalkyl" and "cycloalkylene" mean the monovalent and divalentresidues remaining after removal of one and two hydrogen atoms,respectively, from a cyclic hydrocarbon having 3 to 12 carbon atoms;

"substantially perfluorinated" means hydrocarbon groups in which atleast 50 percent of the hydrogen atoms have been replaced by fluorine;

"core" means a fibril, a grating, a surface, or any other solid mediumthrough which optical information can be transmitted;

"catenary" means in the backbone; and

"relatively optically transparent" means having an optical loss value ofno more than 1000 decibels (dB) per kilometer (km).

The fluorinated acrylamide silane monomers of the present inventionexhibit high rates of free radical homo- and copolymerization and yieldtoughened polymers compared to those resulting from correspondingacrylate- or methacrylate-functional monomers. The acrylamidefunctionality also offers other advantages as a polymerizable groupcompared to an acrylate. For instance, the amide group is known to bemore difficult to hydrolyze than an ester group, and amide-functionalpolymers therefore are more environmentally stable. Despite theseadvantages, fluorinated acrylamide silane monomers have not beenreported.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The present invention provides a new class of polymerizable fluorinatedacrylamide silane monomers preferably having general Formula III below:##STR2## wherein: R¹ and R⁶ are independently hydrogen or methyl;

R² and R³ independently can be an alkyl, preferably methyl, cycloalkyl,or aryl group, or R² and R³ taken together with the carbon to which theyare joined can form a carbocyclic ring containing 4 to 12 ring atoms;

R⁴ and R⁵ are independently hydrogen or lower alkyl;

R⁷ can be alkylene, cycloalkylene, or arylene;

R⁸ can be hydrogen or lower alkyl, preferably ethyl or methyl;

a is 0 or 1;

X is a carbon-to-carbon single bond, CH₂, CH₂ OCH₂, or CH₂ CH₂ OCH₂ ;and

R_(F) is a substantially perfluorinated alkylene, cycloalkylene, orarylene group, optionally comprising up to 6 catenary non-peroxidicoxygen atoms;

The overall process, including a subsequent free radical polymerizationsequence is illustrated in Chemical Scheme I below, in which preferredreactants such as 2-vinyl-4,4-dimethyl azlactone (VDM) and1H,1H,7H,7H-tetrahydroperfluoro(2-methyl-3-oxa-heptane)-1,7-diol areused to illustrate the process by which the fluorinated acrylamidesilane monomers are prepared.

In the initial reaction (step A) a 2-alkenyl azlactone (Formula IV)##STR3## wherein R¹, R², R³, R⁴, R⁵, and a are as previously defined,reacts with a fluorinated diol having the general Formula V: ##STR4##wherein: R_(F), R⁶, and X are as previously described, to yield ahydroxy-functional fluorinated acrylamide of Formula VI, ##STR5##wherein: R¹, R², R³, R⁴, R⁵, R⁶, X, R_(F) and a are as previouslydescribed.

In a second step, condensation of the hydroxy-functional fluorinatedacrylamide with an isocyanatoalkylsilane provides a fluorinatedacrylamide silane monomer of the invention having general Formula III.

In a third step (step C) the fluorinated acrylamide silane monomer ispolymerized through the carbon-carbon double bond to provide units of ahomopolymer. ##STR6##

Useful 2-alkenyl azlactones for the present invention include:2-vinyl-4,4-dimethyl-2-oxazolin-5-one,2-isopropenyl-4,4-dimethyl-2-oxazolin-5-one,2-vinyl-4-ethyl-4-methyl-2-oxazolin-5-one,2-vinyl-4,4-diethyl-2-oxazolin-5-one,2-vinyl-4-methyl-4-phenyl-2-oxazolin-5-one,2-isopropenyl-4,4-tetramethylene-2-oxazolin-5-one,2-vinyl-4,4-pentamethylene-2-oxazolin-5-one, and2-vinyl-4,4-dimethyl-2-oxazin-6-one. The preferred 2-alekyl azlactone,because of its reactivity and commercial availability, is2-vinyl-4,4-dimethyl-2-oxazolin-5-one (SNPE, Inc. Princeton, N.J.).

Useful fluorinated diols in the present invention include:

(1) 2,2-difluoro-1,3-propanediol,

(2) 2,2,3,3-tetrafluoro-1,4-butanediol,

(3) 2,2,3,3,4,4-hexafluoro-1,5-pentanediol,

(4) 2,2,3,3,4,4,5,5-octafluoro-1,6-hexanediol,

(5) 2,2,3,3,4,4,5,5,6,6-decafluoro-1,7-heptanediol,

(6) 2,2,3,3,4,4,5,5,6,6,7,7-dodecafluoro-1,8-octanediol,

(7) 1H,1H,7H,7H-tetrahydro-perfluoro[2-methyl-3-oxa-heptane]-1,7-diol,and

(8) 1H,1H,8H,8H-tetrahydro-perfluoro[2-methyl-3-oxa-octane]-1,8-diol.

The preferred fluorinated diol because of its reactivity is1H,1H,7H,7H-tetrahydro-perfluoro[2-methyl-3-oxa-heptane]-1,7-diol.Compounds (1) through (7) are commercially available from MinnesotaMining and Manufacturing Company, St. Paul, Minn. Compound (8) can beprepared as described in U.S. Pat. No. 3,574,770, Example 1. Otherfluorinated diols useful in the invention, especially when low meltingacrylamide reaction products are desired, are those described in U.S.Pat. No. 4,906,792, which is incorporated herein by reference.

The reaction of a 2-alkenyl azlactone and a fluorinated diol (step Aabove) to prepare the hydroxy-functional fluorinated acrylamide monomer,is facilitated by the presence of a catalyst. Useful catalysts include1,8-diazabicyclo[5.4.0]undec-7-ene (DBU),1,5-diazabicyclo[4.3.0]non-5-ene (DBN), 1,4-diazabicyclo[2.2.2]octane(DABCO), triethylamine, tripropylamine, tributylamine, trihexylamine,trioctylamine, and tridecylamine. These compounds are commerciallyavailable from Aldrich Chemical Co., Milwaukee, Wis. Polymeric-supportedcatalysts such as those described by Tomoi in Makromol. Chem., 1984,185, 2117, can also be employed as useful catalysts.

Ion-exchange resins can also be employed as catalysts; examples includeAmberlite™ IRA-68 ion exchange resin (available from Rohm & Haas,Philadelphia, Pa.); Amberlite™ IRA-938 ion exchange resin, Amberlite™IRA-400 ion exchange resin, Amberlite™ IRA-401 S ion exchange resin, andAmberlite™ IRA-410 ion exchange resin (available from MallinckrodtSpecialty Chemicals Co., Paris, Ky.). Concentrations of the catalystsrange from 0.1 to 20 weight percent, preferably 0.25 to 5.0 weightpercent, and most preferably 0.5 to 2.0 weight percent based on theazlactone reactant; triethylamine and Amberlite™ IRA-68 ion exchangeresin are preferred.

In a typical procedure, equal molar quantities of 2-alkenyl azlactoneand fluorinated diol are mixed with the catalyst in the absence ofsolvent. Alternatively, organic solvents may be employed with theproviso that they not react with the azlactone or catalyst under thereaction conditions. Suitable organic solvents include ethyl acetate,toluene, tetrahydrofuran (available from Aldrich Chemical Co.,Milwaukee, Wis.), and solvents such as Freon™ 113 fluorinated solvent(available from E. I. Dupont de Nemours & Co., Wilmington, Del.).Especially with the preferred catalysts and a solvent-free reactionsolution, a mildly exothermic reaction will ensue, and the reaction isgenerally complete as determined by infrared spectroscopy when thereaction temperature returns to ambient. With other catalysts and whensolvents are employed, warming the reaction mixture will hastencompletion of the reaction. Suitable warming temperatures are from40°-80° C.; preferably 40°-65° C., for a period of 0.5 to 12 hours,preferably 0.5 to 2 hours.

In the case of ion-exchange resins, the catalyst may be efficientlyremoved from the reaction product by filtration. The catalyst may berejuvenated by washing the ion exchange resin with alkali and drying.Other catalysts may be removed from the reaction product bydistillation.

It is generally advisable to add a free radical stabilizer such asphenothiazine or 2,6-di-t-butyl-p-cresol in concentrations by weightbased on reaction product from 0.001 to 1.0 percent, preferably 0.05 to0.15 percent. Useful isocyanatoalkylsilanes in the present inventioninclude 2-isocyanatoethyltrimethoxysilane,3-isocyanatopropyltrimethoxysilane, 2-isocyanatoethyltriethoxysilane,and 3-isocyanatopropyltriethoxysilane, with3-isocyanatopropyltriethoxysilane (available from Petrarch Systems,Bristol, Pa.) being preferred. Reactions may take place at ambienttemperature. In a typical procedure, equal molar quantities of the aboveprepared hydroxy-functional fluorinated acrylamide andisocyanatoalkylsilane are mixed in the absence of solvent.Alternatively, organic solvents, as noted above, may be employed withthe proviso that they not react with the reactants under the reactionconditions. The condensation reaction is enhanced in the presence ofminor amounts, i.e. 0.01 to 1.0 weight percent, of a catalyst. Suitablecatalysts are tertiary amines and metal salts or complexes of organiccompounds. Examples of tertiary amines include:N,N-dimethylaminoethanol, N,N-dimethylcyclohexylamine,diaminobicyclooctane (DABCO), and N,N'-diethylpiperazine. Examples ofmetal salts or complexes of organic compounds include: stannous octoate,dibutyltin dilaurate, dibutyltin thiocarboxylates, and ferricacetylacetonate. A thorough discussion on catalyst systems can be foundin the book by G. Woods "The ICI Polyurethanes Book" Wiley & Sons: NewYork, 1987, pp 41-45. The preferred catalyst is dibutyltin dilaurate andis available from Aldrich Chemical Co., Milwaukee, Wis.

By reason of the acrylamide functionality, novel and useful polymers ofthe invention are obtained by polymerization of monomers of Formula IIIto form homopolymers and copolymers having units of Formula VII,##STR7## wherein R¹, R², R³, R⁴, R⁵, R⁶, R⁷, R⁸, R_(F), X, and a are aspreviously defined, to provide the polymers with approximate molecularweights in the range of 2,000 to 5,000,000.

Copolymers can be formed from the fluorinated acrylamide silane monomersof the present invention with any compatible ethylenically-unsaturatedmonomer in any proportion. Copolymers are preferably prepared by mixingcompatible monomers with the monomers of the invention in the presenceof free radical catalysts in the presence of heat or UV irradiation asnecessary to obtain the desired reaction rate. Examples include: (a)with acrylates or methacrylates such as methyl(meth)acrylate,lauryl(meth)acrylate, dodecyl(meth)acrylate,perfluorooctyl(meth)acrylate, and the like; (b) with styrenes such asstyrene, alpha-methylstyrene, and parachlorostyrene; (c) withacrylamides and methacrylamides such as acrylamide,N,N-dimethylacrylamide, N-isopropylacrylamide, and N-phenylacrylamide;(d) with ethylenically-unsaturated monomers such as vinyl chloride,vinyl acetate, vinylidene fluoride, and vinyl azlactones, and (e) withallyl derivatives, such as diallyl phthalate, triallyl cyanurate, andthe like. Preferably the copolymer contains at least 0.25 percent byweight of the fluorinated acrylamide silane monomer in the invention andpreferably at least 5.0 weight percent up to 99 weight percent.Copolymers of the invention can be used as non-wetting agents.

As is known to those skilled in the art, when monomers of the inventionform copolymers, units selected from the above structures and comonomerunits may react in any proportion and will be distributed throughout thepolymer in a more or less random fashion depending upon the comonomerand the degree of similarity of its polymerization kinetics to themonomer of Formula III.

Polymerization of the monomers may be carried out by employinginitiators which generate free radicals on application of activatingenergy as is conventionally used in the polymerization ofethylenically-unsaturated monomers. Included among useful free radicalinitiators are thermally activated initiators such as organic peroxides,organic hydroperoxides, and azo compounds. Representative examples ofsuch initiators include benzoyl peroxide, tertiary-butyl perbenzoate,diisopropyl peroxydicarbonate, cumene hydroperoxide,azobis(isobutyronitrile), and the like. Generally, from about 0.1 to 10percent by weight of thermal initiator is used.

Actinic radiation may be utilized to initiate polymerization. Highenergy electrons emitted from commercial electron beam generators arecommonly employed in these ionizing radiation systems. Photoinitiatorsmay also be employed to initiate polymerization. Such initiators arewell known and have been described in the polymerization art, e.g.,Chapter II of "Photochemistry" by Calvert and Pitts, John Wiley and Sons(1966). Preferred photoinitiators are those which facilitatepolymerization when the composition is irradiated with ultravioletlight. Representative examples of such initiators include acyloin andderivatives thereof, such as benzoin, benzoin ethyl ether, benzoinisopropyl ether, alpha-methylbenzoin; diketones such as benzil, anddiacetyl, etc.; ketones such as acetophenone, methyl benzoylformate,2-hydroxy-2-methyl-1-phenyl-1-propanone, benzophenone, and the like.Normally, the photoinitiator is used in amounts ranging from about 0.001to 10 percent by weight of the total monomeric composition. Preferably,about 0.05 to 1.0 percent of photoinitiator is used in the polymerizablecompositions.

When the activating energy is only heat, polymerization is usuallycarried out at a temperature in the range of 40° to 140° C. for about 5to 48 hours. It is to be understood that polymerization conditions arenot limited to the stated temperature or time conditions, nor isinitiation limited to use of ultraviolet radiation or heat alone, butcombination may be employed as well.

The novel fluorinated acrylamide silane monomers of the inventionprovide novel claddings for siliceous cores and transparent organicpolymer cores and substrates which are useful for transmitting opticalinformation. These compositions are disclosed in the aforementioned U.S.Ser. No. 07/750,092, now U.S. Pat. No. 5,239,026 which is incorporatedherein by reference.

Representative polymer cores and supports include poly(methylmethacrylate), poly(styrene), and poly(carbonates). The claddingmaterials are the free radical polymerization products of theabove-referenced coating compositions selected to provide a refractiveindex lower than that of the core, preferably at least 0.03 units less,more preferably at least 0.05 units less than the refractive index ofthe core. Typically cores have diameters in the range of 100 to 1000micrometers, and claddings can range in thickness from 5 to 100micrometers. The cladding compositions may also comprise a thermalstabilizer/antioxidant.

The monomers of the invention are useful as adhesion-promotingcomponents in cladding compositions for optical fibers. Informationtransfer using a modulated light beam guided by optical fibers can haveapplications, for example, in telecommunications and computer link-ups.Due to the increase of numerical aperture (NA), other applications suchas laser delivery systems where real time sensing capabilities arefeasible with the cladding compositions of the present invention. Theseoptical fiber linkages have advantages compared to metal wires carryingelectrical signals in that they have very high information carryingcapacities and are free from external interferences, such aselectromagnetic interference.

The monomers of the invention can be polymerized to form homopolymersand copolymers which are useful as non-wetting agents.

Objects and advantages of this invention are further illustrated by thefollowing examples, but the particular materials and amounts thereofrecited in these examples, as well as other conditions and details,should not be construed to unduly limit the invention.

EXAMPLE 1

This Example teaches preparation of a fluorinated acrylamide silanemonomer in accordance with the scheme below: ##STR8## Step A:1H,1H,7H,7H-tetrahydro-perfluoro(2-methyl-3-oxa-heptane)-1,7-diol(available from Minnesota Mining & Manufacturing, St. Paul, Minn.)(41.05 grams, 0.125 mole) and 2-vinyl-4,4-dimethylazlactone (VDM) (SNPE,Inc., Princeton, N.J.) (17.41 grams, 0.125 mole) were mixed to provide ahomogeneous solution. To this solution was added dry Amberlite™ IRA-68polymeric resin (Rohm & Haas, Philadelphia, Pa.) (3.00 grams, 5.6meq/gram). The reaction mixture was then shaken for five hours at roomtemperature and thirty hours at 70° C. An infrared spectrum showedcharacteristic absorptions for the acrylamide product. The crude productwas dissolved in a solvent mixture of chloroform and Freon™ 113fluorinated solvent (E.I. Dupont de Nemours & Co., Wilmington, Del.)(5:1) (250 mL), and the insoluble polymeric resin was filtered. Thefiltrate was treated with water (30 mL) containing 5 drops oftrifluoroacetic acid and stirred overnight. The contents of the flaskwere poured into a separatory funnel. The organic layer was separated,dried over anhydrous magnesium sulfate, and filtered. The filtrate wasconcentrated using a rotary evaporator to leave the desiredhydroxy-functional fluorinated acrylamide.

Step B: In a one-necked 250 mL round-bottomed flask, were added theproduct from Example 1 (24.27 grams, 0.052 mole) and3-isocyanatopropyltriethoxysilane (Petrarch Systems, Bristol, Pa.)(12.85 grams, 0.052 mole). The mixture was stirred at room temperatureunder a nitrogen atmosphere and treated with 2 drops of dibutyltindilaurate (Aldrich Chemical Co., Milwaukee, Wis.). The reaction mixturewas allowed to stir an additional 16 hours at which time spectralanalysis confirmed the presence of the desired fluorinated acrylamidesilane monomer.

Similarly, using fluorinated diols designated (1) through (8) above,other alkenyl azlactones mentioned above, and otherisocyanatoalkylsilanes mentioned above, a variety of fluorinatedacrylamide silane monomers can be prepared.

EXAMPLE 2

This example teaches the use of copolymers containing fluorinatedacrylamide silanes as claddings components for optical fibers. Amonomeric cladding composition was prepared using the fluorinatedacrylamide silane from Example 1, as follows:

    ______________________________________                                        Monomers                                                                      ______________________________________                                        (perfluorocyclohexyl) methyl acrylate (3M,                                                             91.0 grams                                           St. Paul, MN)                                                                 fluorinated diacrylate (prepared as in                                                                 5.0 grams                                            U.S. Pat. No. 3,055,932, Example 1)                                           fluorinated acrylamide silane (from                                                                    2.0 grams                                            Example 1)                                                                    Darocur ™ initiator 1173 (E. M. Merck                                                               2.0 grams                                            Industries, Hawthorne, NY)                                                    ______________________________________                                    

The apparatus for producing the optical fiber was a 6.7 meter (22 foot)Astro Tower equipped with an Astro Graphite Resistance Furnace(available from the Astro Division of Thermal Technologies, Santa Rosa,Calif.). The glass core material emanated from a Diasil Preform Rod(available from Mitsubishi Rayon Co., Ltd., Tokyo, Japan), and thecoating station, where the cladding composition was applied, was an opencup design. Ultraviolet actinic radiation was supplied by a mediumpressure mercury lamp, and irradiation of the coated monomeric claddingcomposition to provide a copolymer took place in an atmosphere ofnitrogen; the optical fiber was produced at a constant speed of 20meters/minute.

A 600 meter length of the optical fiber consisting of a 200 micrometerglass core and a 25 micrometer clad was overcoated with a Tefzel™ 210fluorinated polymeric buffer coating (E. I. Dupont de Nemours,Wilmington, Del.) by coextrusion. The principle of overcoating anoptional fiber with Tefzel™ 210 fluoropolymer is discussed by M. M.Ramsay in Chapter 2 of the book entitled "Fiber Optics Handbook", McGrawHill: New York, 1989, pp 2.13-2.20. The resultant optical fiberexhibited a loss of 4.3 dB/km. The loss measurement was obtained using aTektronix™ 506 Optical Time Domain Reflectometer (OTDR) (available fromTektronix, Portland, Oreg.) with the loss value at 812 nm beingrecorded. The principle of the OTDR measurement is discussed by D.Marcuse in his book entitled "Principles of Optical Fiber Measurements",Academic Press: New York, 1981, pp 236-241, and procedures utilized werethat of Electronic Industries Association Standard 455-46 (May 1983).The numerical aperture (NA) of a 2 meter length of the optical fiber wasmeasured to be 0.46, at 633 nm. The principle of the NA measurement isdiscussed by D. L. Philen and W. T. Anderson in Chapter 8 of the bookentitled "Optical Fiber Telecommunications II", Academic Press: NewYork, 1988, pp 331-332, and test methods utilized were that ofElectronic Industries Association Standard 455-47 (May 1983).

EXAMPLE 3

    ______________________________________                                        Monomers                                                                      ______________________________________                                        (perfluorocyclohexyl) methyl acrylate                                                                86.0 grams                                             fluorinated diacrylate (as prepared in                                                               10.0 grams                                             U.S. Pat. No. 3,055,932, Example 1)                                           fluorinated acrylamide silane (from                                                                   2.0 grams                                             Example 1)                                                                    Darocur 1173            2.0 grams                                             ______________________________________                                    

A 1.2 kilometer section of an optical fiber over-coated with Tefzel™ 210prepared as in Example 2 exhibited a loss of 3.7 dB/km. Using theprocedure of Example 2 the NA measurement of this optical fiber wasfound to be 0.45. The strength of the fiber was determined by prooftesting the fiber at 3.45×10⁹ dynes/cm² (50 kpsi) without evidence ofoptical loss change. The principle of proof testing optical fibers isdiscussed by F. C. Allard in his book entitled "Fiber Optics HandbookFor Engineers and Scientists", McGraw-Hill, Inc.: New York, 1990, pp1.40-1.41 and 4.49-4.52 and test methods utilized were that of FiberOptic Test Procedures, FOTP-31.

EXAMPLE 4

    ______________________________________                                        Monomers                                                                      ______________________________________                                        (perfluorocyclohexyl) methyl acrylate                                                                83.0 grams                                             fluorinated diacrylate (as prepared in                                                               10.0 grams                                             U.S. Pat. No. 3,055,932, Example 1)                                           fluorinated acrylamide silane (from                                                                   5.0 grams                                             Example 1)                                                                    Darocur 1173            2.0 grams                                             ______________________________________                                    

A 1.2 kilometer section of an optical fiber over-coated with Tefzel 210prepared as in Example 2 exhibited a loss of 4.2 dB/km. Using theprocedure of Example 2 the NA measurement of this optical fiber wasfound to be 0.44. Using the procedure of Example 3, the strength of thefiber was determined by proof testing the fiber at 3.45×10⁹ dynes/cm²(50 kpsi) without evidence of optical loss change.

EXAMPLE 5

This example teaches the use of the fluorinated acrylamide silanehomopolymer of the invention as a non-wetting agent.

    ______________________________________                                        Preparation of the fluorinated acrylamide                                     silane homopolymer                                                             Charge:                                                                      ______________________________________                                        fluorinated acrylamide silane (from                                                                   14.2   grams                                          Example 1)                                                                    ethyl acetate           127.4  grams                                          azobis(iso-butyronitrile)                                                                             0.03   grams                                          ______________________________________                                    

The charge solution was degassed for ten minutes with nitrogen in avessel. The vessel was sealed and heated with agitation at 65° C. for 18hours. At that point, the homopolymer solution was clear and viscous.

A portion of the homopolymer solution was applied to the surface of aclear, clean glass surface. The residual solvent was removed from thehomopolymer coating by slow evaporation at room temperature. Theadvancing contact angle of the treated glass substrate was then measuredutilizing a goneometer with Nujol and glycerol. In comparative example6, a commercial silane, 3-(trimethyoxysilyl)propyl methacrylate, AldrichChemical Co., was similarly tested as a non-wetting agent. The contactangles obtained are shown in TABLE I below.

                  TABLE I                                                         ______________________________________                                        Contact Angle                                                                                                     Surface                                           Silane                      Tension                                   Example tested     Nujol    Glycerol                                                                              (dynes/cm)                                ______________________________________                                        6       commercial 37°                                                                              81°                                                                           28.1                                      (compara-                                                                     tive)                                                                         5       invention  48°                                                                             103°                                                                           23.0                                      ______________________________________                                    

The above data indicates that the homopolymer of Example 5 is superiorto the commercial silane homopolymer in its non-wetting characteristics.

A comonomer, such as methyl (meth)acrylate, can be added to thepolymerizable composition to provide a novel non-wetting agent.

Various modifications and alterations of this invention will becomeapparent to those skilled in the art without departing from the scopeand spirit of this invention, and it should be understood that thisinvention is not to be unduly limited to the illustrative embodimentsset forth herein.

What is claimed is:
 1. A polymer comprising fluorinated acrylamidesilane units, wherein said units have the formula ##STR9## wherein R¹and R⁶ are independently hydrogen or methyl;R² and R³ independently canbe an alkyl, cycloalkyl, or aryl groups, or R² and R³ taken togetherwith the carbon to which they are joined can form a carbocyclic ringcontaining 4 to 12 ring atoms; R⁴ and R⁵ are independently hydrogen orlower alkyl; R⁷ is alkylene, cycloalkylene, or arylene; R⁸ is hydrogenor lower alkyl; a is zero or 1; X is a carbon-to-carbon single bond,CH₂, CH₂ OCH₂, or CH₂ CH₂ OCH₂ ; and R_(F) is a substantiallyperfluorinated alkyl, cycloalkyl, or aryl group, comprising 0 to 6catenary non-peroxidic oxygen atoms.
 2. The polymer according to claim 1wherein R¹ is hydrogen.
 3. The polymer according to claim 1 wherein R¹is methyl.
 4. The polymer according to claim 1 wherein a=zero.
 5. Thepolymer according to claim 1 wherein R⁴ and R⁵ are each hydrogen.
 6. Thepolymer according to claim 1 wherein R⁸ is methyl, ethyl or hydrogen. 7.The polymer according to claim 1 whereinR¹ is H, R² is CH₃, R³ is CH₃,a=0, each R⁶ is H, R_(F) =(CF₂)₃ OCF(CF₃), each X=carbon-to-carbonsingle bond, R⁷ =(CH₂)₃, R⁸ =C₂ H₅.
 8. The polymer according to claim 1which is a non-wetting agent.
 9. The polymer according to claim 1 whichis a homopolymer.
 10. The polymer according to claim 1 which is acopolymer further comprising units derived from a compatibleethylenically unsaturated monomer by copolymerization.